Oxygen is carried by red blood cells and delivered to the heart muscle via the coronary arteries. O...
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Oxygen is carried by red blood cells and delivered to the heart muscle via the coronary arteries. Over the years, the insides of the coronary arteries can narrow. The most common cause is a build-up of plaque. As the insides of the arteries become narrow, blood flow is reduced, and your heart has to work harder to get the oxygen it needs. Sometimes plaque that has built up breaks apart, or a blood clot forms, and blood flow to the heart is suddenly and severely reduced. The pain does not go away with rest or the medications that relieve stable angina. This condition is called unstable angina. It is a medical emergency because without blood-carrying oxygen, the heart muscle dies. This death of heart muscle due to lack of oxygen is what we commonly call a heart attack.